package com.tourlaid.mamagerment.util;

import org.springframework.util.StringUtils;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class MD5Util {

    private static String byteArrayToHexString(byte b[]) {
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++)
            resultSb.append(byteToHexString(b[i]));

        return resultSb.toString();
    }

    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0)
            n += 256;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }

    public static String MD5Encode(String origin, String charsetname) throws UnsupportedEncodingException, NoSuchAlgorithmException {
        if (StringUtils.isEmpty(origin)) {
            return null;
        }
        String resultString = null;
        MessageDigest md = MessageDigest.getInstance("MD5");
        if (StringUtils.isEmpty(charsetname))
            resultString = byteArrayToHexString(md.digest(origin.getBytes("UTF-8")));
        else
            resultString = byteArrayToHexString(md.digest(origin
                    .getBytes(charsetname)));
        return resultString;
    }

    public static String MD5Encode(String origin) throws UnsupportedEncodingException, NoSuchAlgorithmException {
        if (StringUtils.isEmpty(origin)) {
            return null;
        }
        MessageDigest md = MessageDigest.getInstance("MD5");
        return byteArrayToHexString(md.digest(origin.getBytes("UTF-8")));
    }

    private static final String hexDigits[] = {"0", "1", "2", "3", "4", "5",
            "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};

}
